var obj = {
  width: 100,
  height: 100
}

//先缓存在运算
var test = (obj) => {
  let w = obj.width;
  let h = obj.height;
  return w * h;
}

//表达式直接使用
var test = (obj) => {
  return obj.width * obj.height;
}

//结构清晰
var test1 = () => {
  var name = 'zcb';
  var age = 30;
  var slogan = "大前端";
  return name + age + slogan
}

//声明减少
var test1 = () => {
  var name = 'zcb', age = 30, slogan = "大前端";
  return name + age + slogan
}